[SOLVED] Error creating timer in rule

Setup, Configuration and Use Scripts & Rules
1

I just started playing with rules, and my first one is intended to turn the lights out if no motion is detected for five minutes. I have an error in the logs I can make no sense of :slight_smile:

Running openHAB 2.2.0 Build #1133; this is the error:

2017-12-13 01:58:02.248 [ERROR] [ntime.internal.engine.RuleEngineImpl] - Rule 'Office Motion Detected': An error occurred during the script execution: Couldn't invoke 'assignValueTo' for feature JvmVoid: (eProxyURI: office.rules#|::0.2.0.2.0.4::0::/1)

It’s being triggered by this block in the rule:

   timer = createTimer(now.plusMinutes(5)) [|
     logInfo("Office motion not detected; lights out")
     //sendCommand(Office_Lights, OFF)
   ]

Here’s the complete rule file:

var occupiedTimer = null

rule "Office Motion Detected"
when
  Channel "dlinksmarthome:DCH-S150:6c7220c50bc1:motion" triggered
then
  logInfo("OFFICE_MOTION", "Office motion detected")
  //postUpdate(OfficeOccupancyLastUpdated, new DateTime())
  logInfo("OFFICE_MOTION", "Office motion detected -- occupancy updated")

  if (occupiedTimer !== null) {
    logDebug("OFFICE_MOTION", "Office motion detected -- timer cleared")
    occupiedTimer.cancel
  }

  logInfo("OFFICE_MOTION", "Office motion detected -- reset timer")
  timer = createTimer(now.plusMinutes(5)) [|
    logInfo("Office motion not detected; lights out")
    //sendCommand(Office_Lights, OFF)
  ]
end

Any help appreciated…

2

Change to var Timer occupiedTimer = null

Probably not 100% necessary, but it’s a good practice to be explicit about the type.

More importantly, change timer to occupiedTimer

1 Like
3

Oh wow… Thanks for pointing out the mistake – that error message could use some refinement! Also, thanks for the tip on explicitly typing variables.

Laurie

4

In this case it is necessary. The way the Rules Engine is able to infer the Type for a variable is by the type of the object on the right side of the =. Since null is not of type Timer it can’t set the type for occupiedTimer correctly. In all other cases except when you initialize a variable to null the type can be inferred.

1 Like
5

Makes total sense. Thanks for the info!